/*

* Definition for singly-linked list.

* struct ListNode {

* int val;

* struct ListNode *next;

* };

*/

struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) {

struct ListNode *head = NULL;

struct ListNode *walk = NULL;

struct ListNode *tmp = NULL;

int carry = 0;

int val1 = 0;

int val2 = 0;

int val = 0;

while(l1 != NULL || l2 != NULL || carry) {

val1 = 0;

val2 = 0;

val = 0;

if(l1) {

val1 = l1->val;

l1 = l1->next;

}

if(l2) {

val2 = l2->val;

l2 = l2->next;

}

val = carry + val1 + val2;

carry = val / 10;

tmp = malloc(sizeof(struct ListNode));

tmp->val = val % 10;

tmp->next = NULL;

if(!head) {

head = walk = tmp;

} else {

walk->next = tmp;

walk = walk->next;

}

}

return head;

}